Plural defibering zones in a pulping apparatus



April 30, 1968 D. R. HATTON 3,380,669

PLURAL DEFIBERING ZONES IN A PULPING APPARATUS Filed Afiril 11, 1966 2 Sheets-Sheet 1 FIG-3 24 3/ 33 INVENTOR.

DERALD R. HATTON ATTORNEYS April 30, 1968 D. R. HATTON 3,380,669

FIJURAL) DEFIBERING ZONES IN A PULPING APPARATUS Filed April 11, 1966 2 Sheets-Sheet 2 United States Patent 3,380,669 PLURAL DEFIBERING ZONES IN A PULPING APPARATUS Derald R. Hatton, Middlctown, Ohio, assignor to The Black Clawson Company, Hamilton, Ohio, a corporation of Ohio Filed Apr. 11, 1966, Ser. No. 541,817 4 Claims. (Cl. 241-43) This invention relates to pulping apparatus for use in preparing paper making stock, and more particularly to improved apparatus including a pulping unit which produces a substantial increase in pulping efiiciency by providing a more effective defibering action.

The present invention has special relation to the pulping apparatus disclosed in Vokes Patent No. 3,073,535, which issued Jan. 15, 1963 to the assignee of this application. That is, the apparatus of the present invention is used for defibering paper pulp material such as waste paper as it may be received in various forms, as for example, in the form of broke produced when the web breaks in a paper making machine. In general, the apparatus of the present invention is similar to the apparatus shown in the above patent in that it includes a tub or tank which is adapted to receive either batches or a continuous supply of pulp material, and further includes a pulping unit which is located either in a bottom or side wall of the tank. This unit basically includes a rotor and means for driving the rotor to circulate a mixture of pulp material and water within the tank in a generally vortical pattern so that the rotor is effective to produce the desired pulping, reducing and defibering action.

It is a primary object of the present invention to provide improved pulping apparatus which produces a more effective and intensified defibering action whereby the pulp is defibered in a substantially shorter period of time and substantially less total power is required to defiber completely a predetermined quantity of pulp.

As another object, the present invention provides pulping apparatus wherein the stock is circulated by the rotor in such a manner to prevent jamming or binding of the rotor.

As a more specific object, the present invention provides apparatus as outlined above including a series of spaced attrition bars formed on the rotor and on a stationary bedplate positioned directly under the rotor, and the rotor includes vanes projecting outwardly from the bars whereby the vanes cooperate with a series of inlet openings formed within the bedplate to provide preliminary defibering of the stock and further cooperate with the attrition bars to produce a positive centrifugal flow of stock between the bars, which in turn provide a more intensive defibering action on the stock.

Another object of the invention is to provide apparatus as outlined above including means for effecting a high flow rate of stock for preliminary defibering between the rotor vanes and the inlet openings within the bedplate, and means for effecting a more intensive defibering action at a variable rate according to the consistency of the stock to prevent jamming or binding of the stock between the rotor and the bedplate.

Still another object of the invention is to provide apparatus as outlined above including a series of outlet openings formed within the bedplate and surrounding the inlet openings so that slushed stock or slurry can be recirculated by the rotor vanes back into the tank to obtain a high circulation rate for preliminary defibering. and also to provide for clean and rapid dumping or draining of completely defibered stock from the tank.

It is also an object of the invention to provide apparatus as outlined above wherein all of the stock is continuously circulated so that no undefibered stock can lodge within the chamber under the bedplate and thereby contaminate the defibered stock.

Other objects and advantages of the invention will be apparent from the following description, the accompanyin g drawings and the appended claims.

In the drawings:

FIG. 1 is a view partly in side elevation and partly in vertical cross section showing pulping apparatus embodying an improved pulping unit constructed in accordance with the invention;

FIG. 2 is a fragmentary plan view of the pulping apparatus of FIG. 1;

FIG. 3 is an enlarged fragmentary section view of the pulping unit taken generally along the line 33 of FIG. 2;

FIG. 4 is a sectional view of a typical rotor vane as taken along the line 4-4 of FIG. 2 and showing its posi tion relative to the bedplate;

FIG. 5 is a fragmentary bottom view of the rotor;

FIG. 6 is a fragmentary section on the line 66 of FIG. 5;

FIG. 7 is a fragmentary top view of the bedplate; and

FIG. 8 is a fragmentary section on the line 8-8 of FIG. 6.

Referring to the drawings, which illustrate a preferred embodiment of the present invention, FIG. 1 shows pulping apparatus which is somewhat similar in construction with the apparatus disclosed in the above Vokes patent. Generally, the apparatus includes a tub or tank 10 supported by a frame 11 and having a cylindrically shaped side wall 12 extending upwardly from a frusto-conical shaped bottom wall 13 to define a stock receiving chamber. A series of bafile vanes 14 are mounted on the bottom wall 13 and project upwardly adjacent the side wall 12. Mounted within the central portion of the bottom wall 13 is a pulping unit 15 which includes a drive transmission 16 supported on a base 18. The drive transmission 16 includes a vertically extending output shaft 20 (FIG. 3) and a horizontally extending input shaft 21 which is driven by a suitable motor (not shown) through a belt drive connected to a pulley 22.

Referring to FIG. 3, the pulping unit 15 includes a mounting ring or flange 24 which is secured to the bottom wall 13 as by suitable screws (not shown). The flange 24 is rigidly connected through an annular flat plate 25 and a ring 26 to a cylindrical hub 27 which retains an annular seal 28 and a series of packing rings 29 for rotatably sealing the output shaft 20. Formed within the flange 24 is a counterbore 31 in which is mounted an annular bedplate 32 having a flat working face 33. A series of screws 34 secure the bedplate 32 to the flange 24 and support ring 36 is connected to the plate 25 by a series of angularly spaced radially extending ribs 38 and provides a support for the inner or central portion of the bedplate 32, which is secured to the ring 36 by a series of screws 39. The bedplate 32 cooperates with the plate 25 to define an annular chamber 40 through which the ribs 38 extend. A drain conduit 41 is provided for the chamber 40 for dumping or draining the slurry from the tank 10 after the stock has been defibered.

As shown in FIGS. 3 and 7, the central portion of the bedplate 32 is provided with a series of angularly spaced attrition bars 42 which define corresponding passageways 43 therebetween as shown in FIG. 8. Surrounding the bars 42 and also formed within the bedplate 32 are a series of inlet openings 45 which open into the chamber 40. Preferably, these inlet openings 45 are approximately one-half inch in diameter but may be larger or smaller to change the flow rate of stock through the openings. Formed in the outer annular portion of the bedplate 32 are a series of substantially larger outlet openings 46 (FIG. 7) which, as shown in FIG. 3 also open into the chamber 40.

The rotor 50 includes a hub 51 mounted on the reduced upper end portion of the shaft 20 and secured thereto as by a key (not shown), a collar 52, and a screw 53 which is threaded into the end of the shaft for retaining the collar 52. As shown in FIGS. 2 and 4, extending from the hub 51 of the rotor 50 are a series of angularly spaced vanes 55 which preferably are constructed substantially as shown in the above mentioned patent. Each of these vanes 55 includes an inclined leading edge surface 58 (FIG. 4) which cooperates with the inlet openings 45 to provide a preliminary defibering action on the stock by producing somewhat of a shedding action which forces a portion of the stock down through the inlet openings 45. In addition, the vanes 55 also circulate the stock within the tank 10 to produce the vortical flow pattern which breaks up bulk pieces of the stock into smaller pieces. To provide the best defibering action, it has been found that the angle B (FIG. 4) between the leading edge surface 58 of each vane 55 and a vertical plane should be between 5 and A series of attrition bars 60 (FIG. 5) are formed on the bottom side of the outer annular portion of the rotor 50 inwardly of the vanes 55 and define corresponding elongated passageways 62 (FIG. 6) therebetween in a manner similar to the bars 42 and passageways 43 formed on the bedplate 32. As shown in FIG. 3, when the rotor 50 is assembled, the bars 60 are positioned directly above and adjacent the bars 42 and cooperate therewith to produce an intensive defibering action on the slushed stock or slurry as it is circulated between the bars 60 and 42 within the corresponding passageways 62 and 43.

A booster impeller 65 (FIG. 3), including a hub 67 and a series of uniformly spaced projecting vanes 68, is mounted on the shaft directly under the rotor 50 so that the outer ends of the vanes 68 are spaced adjacent the inner cylindrical edge surfaces of the bedplate 32 and supporting plate 36. Each of the booster impeller vanes 68 is inclined in relation to the axis of the shaft 20 (FIG. 3) so that when the shaft 20 is rotated, the vanes 68 and 55 cooperate to produce a positive flow of the slushed stock or slurry within the chamber as shown by the arrows.

In operation, a portion of the stock or slurry which is forced through the inlet openings by the inclined leading edge surfaces 58 of the rotor vanes 55 is circulated inwardly within the chamber 40 between the ribs 38 by the booster impeller 65 to the inner open ends of the passageways 43 and 62 defined between the attrition bars 42 and 60 respectively. This portion of the stock is then forced outwardly between the attrition bars 42 and 60 as a result of the centrifugal forces produced by the rotating bars 60 and vanes 55 so that the stock is subjected to a more concentrated defibering action.

The remaining portion of the slurry flowing through the inlet openings 45 is circulated outwardly within the chamber 40 and through the outlet openings 46. Thus it can be seen that not all of the slurry which is subjected to the initial defibering action produced between the vanes 55 and the inlet openings 45 is forced through the passageways between the attrition bars 42 and 60. Thus, if stock having a relatively high consistency begins to build up at the inlets of the passageways 43 and 62, a larger portion of the stock is circulated through the outlet openings 46 thereby preventing jamming or bind ing of the stock between the rotor 50 and the bedplate 32. While it has been found that the booster impeller 65 is helpful for producing a high flow of slurry between the attrition bars 42 and 60, the centrifugal action produced by the vanes and bars alone is substantial and is sufiicient without the booster impeller to provide for effective circulation, especially with a slurry having lower stock consistency.

Through testing of various types and consistencies of paper stock, it has been found that a pulping unit constructed in accordance with the present invention pro vides significant advantages and features. For example, when the rotor 50 is driven at a vane tip speed of ap proximately 6000 feet per minute, it has been found that the pulping unit with its spaced relation of the attrition bars 42 and 60, vanes 55 and openings 45, provides a highly efficient and effective defibering action.

Thus even though additional horsepower is required for driving the rotor 50 including the attrition bars at a tip speed of 6000 f.p.m., the time required for completely defibering a predetermined quantity of stock is substantially reduced, and as a result, the total power re quired for defibering the stock is similarly reduced. For example, in one test of comparing a unit constructed in accordance with the present invention and a comparable size unit as shown in the above patent, a power reduction of 25% and a time savings of approximately 50% was achieved to obtain the same degree of complete defibering.

A further advantage of the pulping unit of the present invention is that the positive circulation produced by the vanes 55 and booster impeller prevents stock from lodging within the chamber 40 and thereby prevents contamination of the slurry by pieces of undefibered stock.

It is also a feature that all of the slurry which enters the chamber 40 through the inlet openings 45 does not have to flow through the passageways 43 and 62 defined be tween the corresponding attrition bars 42. and 60. Thus when the flow of slurry between the bars 42 and 60 is reduced by a higher concentration of stock, the initial defibering action between the vanes 55 and inlet openings 45 is not also reduced since a larger portion of the flow will be circulated back into the tank 10 through the outlet openings 46. It has also been found that the large outlet openings 46 provide for rapid and clean dumping or draining of the slurry from the tank 10 through the drain conduit 41 connected to the chamber 40.

While the form of apparatus herein described constitutes a preferred embodiment of the invention, it is to be understood that the invention is not limited to this precise form of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. In pulping apparatus including a tank adapted to receive a batch or a continuous supply of pulp material to be defibered, an improved pulping unit comprising a bedplate, a shaft extending normally to said bedplate, a rotor mounted on said shaft and having a plurality of vanes projecting outwardly over said bedplate in angularly spaced relation, a series of angularly spaced attrition bars formed on the underside of said rotor inwardly of said vanes and defining passageways therebetween, a corresponding series of angularly spaced attrition bars formed on the upper side of said bedplate defining passageways therebetween and positioned directly under said bars on said rotor, means defining a plurality of inlet openings within an annular portion of said bedplate under said vanes, means defining a chamber under said bedplate for connecting said openings to the innermost ends of said passageways defined by said bars, and drive means for rotating said rotor whereby said vanes cooperate with said inlet openings in said bedplate to provide a preliminary defibering action while forcing stock through said openings into said chamber, and said vanes also cooperate with said attrition bars to provide a centrifugal flow of stock from said chamber and through said passageways between said bars where the stock is subjected to a secondary defibering action.

2. Apparatus as defined in claim 1 including a booster impeller mounted on said shaft under said rotor, said impeller including angularly spaced vanes projecting outwardly for cooperation with said vanes on said rotor to produce a positive flow of stock through said passageways between said attrition bars.

3. Apparatus as defined in claim 1 including means defining a plurality of discharge openings within an annular portion of said bedplate surrounding said annular portion under said vanes, and wherein said chamber under said bedplate also connects said inlet openings to said outlet openings to provide for defibering a high capacity of stock between said inlet openings and said vanes without overloading said passageways between said attrition bars providing said secondary defibering action.

4. Apparatus as defined in claim 3 wherein said outlet openings are substantially larger than said inlet openings to avoid restricting the circulation of stock through said inlet openings and back into said tank and to provide for rapid draining of completely defibered stock from said tank.

References Cited UNITED STATES PATENTS 2,424,726 7/ 1947 Wells 24146 2,674,927 4/1954 Wicksell 241-46 3,009,656 11/1961 Martindale 24146 3,073,535 1/1963 Vokes 241-46 3,154,255 10/1964 Schulman et al. 241--46 X WILLIAM W. DYER, JR., Primary Examiner.

F, T. YOST, Assistant Examiner, 

1. IN PULPING APPARATUS INCLUDING A TANK ADAPTED TO RECEIVE A BATCH OR A CONTINUOUS SUPPLY OF PULP MATERIAL TO BE DEFIBERED, AN IMPROVED PULPING UNIT COMPRISING A BEDPLATE, A SHAFT EXTENDING NORMALLY TO SAID BEDPLATE, A ROTOR MOUNTED ON SAID SHAFT AND HAVING A PLURALITY OF VANES PROJECTING OUTWARDLY OVER SAID BEDPLATE IN ANGULARLY SPACED RELATION, A SERIES OF ANGULARLY SPACED ATTRITION BARS FORMED ON THE UNDERSIDE OF SAID ROTOR INWARDLY OF SAID VANES AND DEFINING PASSAGEWAYS THEREBETWEEN, A CORRESPONDING SERIES OF ANGULARLY SPACED ATTRITION BARS FORMED ON THE UPPER SIDE OF SAID BEDPLATE DEFINING PASSAGEWAYS THEREBETWEEN AND POSITIONED DIRECTLY UNDER SAID BARS ON SAID ROTOR, MEANS DEFINING A PLURALITY OF INLET OPENINGS WITHIN AN ANNULAR PORTION OF SAID BEDPLATE UNDER SAID VANES, MEANS DEFINING A CHAMBER UNDER SAID BEDPLATE FOR CONNECTING SAID OPENINGS TO THE INNERMOST ENDS OF SAID PASSAGEWAYS DEFINED BY SAID BARS, AND DRIVE MEANS FOR ROTATING SAID ROTOR WHEREBY SAID VANES COOPERATE WITH SAID INLET OPENINGS IN SAID BEDPLATE TO PROVIDE A PRELIMINARY DEFIBERING ACTION WHILE FORCING STOCK THROUGH SAID OPENINGS INTO SAID CHAMBER, AND SAID VANES ALSO COOPERATE WITH SAID ATTRITION BARS TO PROVIDE A CENTRIFUGAL FLOW OF STOCK FROM SAID CHAMBER AND THROUGH SAID PASSAGEWAYS BETWEEN SAID BARS WHERE THE STOCK IS SUBJECTED TO A SECONDARY DEFIBERING ACTION. 